ABC signed on WENR-TV, Channel 7, in 1948 from Chicago.  

When ABC merged with Untied Paramount Theaters in 1953, it ended up with two TV stations – WENR-TV and UPT’s WBKB-TV, Channel 4.  The FCC made it give up one station.  ABC sold the Channel 4 license to CBS, which formed WBBM-TV.  The station later moved to Channel 2.   

ABC kept Channel 7 and the WBKB-TV call letters.  The station became WLS-TV in 1968.  

The following year, WLS-TV’s newscasts began using the “Eyewitness News” format that sister WABC-TV in New York City adopted.  Anchors Fahey Flynn  and Joel Daly anchored the newscasts into the 1980s. By 1973, Eyewitness News on WLS surpassed WMAQ-TV as the top-rated local news operation in Chicago.  WBBM-TV topped WLS in 1979.  

Fahey died in 1983.  WLS dropped dropped to third place.  The station made changes, including hiring Oprah Winfrey to host its low-rated morning talk show, “A.M. Chicago.”  On-air staff and format changes helped boost WLS’ local news ratings, as noted in this 1985 ad. Channel 7 reclaimed the No. 1 spot by 1986.  It has been the top-rated local TV news operation ever since.

In 1996, WLS dropped the “Eyewitness News” name in favor of “ABC 7 News.”  It brought back the “Eyewitness News” name in 2013.  

Here is a collection of WLS-TV news opens over the decades:

YouTube also has a complete 1981 newscast:

This 1981 promo features Fahey Flynn and other WLS “Eyewitness News” personalities:

Source: Wikipedia (WLS-TV)